1. Field of the Invention
The following disclosure relates to a diaphragm mounting of a brake chamber for a vehicle, and in particular, to a diaphragm mounting of a brake chamber for a vehicle, which may exclude a return spring for restoring a diaphragm to an original position.
2. Description of the Related Art
As well known in the art, a brake system of a commercial vehicle employs an air brake with an excellent braking force and a convenient handling property, and a brake chamber included in the air brake system is classified into spring types, piston types or the like.
If a brake pedal is stepped, air pressure of an air tank is applied to a diaphragm in a brake chamber, and simultaneously a push rod in the brake chamber is pushed to give a mechanical force for braking to a front brake unit and a rear brake unit. If the brake pedal is released, the compressed air in the brake chamber is emitted to the air, and simultaneously the diaphragm and the piston rod move to their original positions by a return spring, thereby releasing the front brake unit and the rear brake unit.
Here, the brake chamber will be described in brief with reference to FIGS. 3 and 4.
The brake chamber 100 includes: a flange case 102 for dividing a space of a spring chamber and a space of a service chamber; a head 106 assembled to the top of the flange case 102 to form a spring chamber 104; a non-pressure chamber 110 assembled to the bottom of the flange case 102 to form a service chamber 108; a spring diaphragm 112 assembled between the head 106 and the flange case 102; a service diaphragm 114 assembled between the flange case 102 and the non-pressure chamber 110; a first return spring 116 compressively disposed between the spring diaphragm 112 and the flange case 102; a second return spring 118 compressively disposed between the service diaphragm 114 and the non-pressure chamber 110; a first push rod 120 having an upper plate closely adhered to the bottom surface of the spring diaphragm 112 and a lower plate closely adhered to the top surface of the service diaphragm 114 through the flange case 102; a piston rod 122 having an upper plate closely adhered to the bottom surface of the service diaphragm 114 and a lower end connected toward a front or rear brake unit (not shown) through the non-pressure chamber 110; a piston 124 positioned between the head 106 and the spring diaphragm 112; and a power spring 140 disposed between the top surface of the piston 124 and the bottom surface of the head 106 to pressurize the piston 124 with an elastic force.
At this time, the top surface of the spring diaphragm 112 is closely adhered to the bottom surface of the piston 124, and the top surface of the spring diaphragm 114 is closely adhered to the lower plate of the push rod 120 and the bottom surface of the flange case 102 simultaneously.
In addition, the space between the head 106 and the spring diaphragm 112 becomes a first spring chamber 104a, the space between the spring diaphragm 112 and the flange case 102 becomes a second spring chamber 104b, and the space between the flange case 102 and the non-pressure chamber 110 becomes the service chamber 108.
Therefore, the operation of such a spring-type brake chamber includes a process in which the piston 124 pressurizes the spring diaphragm 112 with an elastic force generated by expansion of the power spring 140 when air pressure of the first spring chamber 104a discharges, a process in which the push rod 120 moves downwards and simultaneously the service diaphragm 114 is pressurized while compressing the first return spring 116 when the spring diaphragm 112 is pressurized, a process in which the piston rod 122 compresses the second return spring 118 and moves forwards through the non-pressure chamber 110 to protrude when the service diaphragm 114 is pressurized, and a process in which a mechanical force generated by forward movement of the piston rod 122 is transferred to front and rear brake units to perform braking.
At this time, the spring diaphragm 112 has a closed structure and supported by the push rod 120.
In more detail, a push rod plate 130 for supporting the top of the first return spring 116 and a push rod plate 132 closely adhered to the spring diaphragm 112 are assembled and fixed to the top surface of the push rod 120 in order by using screws 134 or the like.
However, since the general spring diaphragm has a closed structure, the return spring guide, the push rod plate, the return spring or the like must be assembled to generate a restoring force for making upward movement after downward movement, which increases the number of parts and manufacture costs.